1 .\" Copyright (c) 2009 Alexander Motin <mav@FreeBSD.org>
2 .\" All rights reserved.
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33 .Nd Serial ATA Advanced Host Controller Interface driver
35 To compile this driver into the kernel,
36 place the following lines in your
37 kernel configuration file:
38 .Bd -ragged -offset indent
44 Alternatively, to load the driver as a
45 module at boot time, place the following line in
47 .Bd -literal -offset indent
51 The following tunables are settable from the loader:
53 .It Va hint.ahci.X.msi
54 controls Message Signaled Interrupts (MSI) usage by the specified controller
59 single MSI vector used, if supported (default);
61 multiple MSI vectors used, if supported;
63 .It Va hint.ahcich.X.pm_level
64 controls SATA interface Power Management for specified channel,
65 allowing some power to be saved at the cost of additional command
70 interface Power Management is disabled (default);
72 device is allowed to initiate PM state change, host is passive;
74 host initiates PARTIAL PM state transition every time port becomes idle;
76 host initiates SLUMBER PM state transition every time port becomes idle.
78 Note that interface Power Management is not compatible with
79 device presence detection.
80 You will have to reset bus manually on device hot-plug.
81 .It Va hint.ahcich.X.sata_rev
82 setting to nonzero value limits maximum SATA revision (speed).
83 Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps.
86 This driver provides the CAM subsystem with native access to the
88 ports of AHCI-compatible controllers.
89 Each SATA port found is represented to CAM as a separate bus with one
90 target, or, if HBA supports Port Multipliers, 15 targets.
91 Most of the bus-management details are handled by the SATA-specific
93 Connected ATA disks are handled by the ATA protocol disk peripheral driver
95 ATAPI devices are handled by the SCSI protocol peripheral drivers
101 Driver features include support for Serial ATA and ATAPI devices,
102 Port Multipliers, hardware command queues (up to 32 commands per port),
103 Native Command Queuing, SATA interface Power Management, device hot-plug
104 and Message Signaled Interrupts.
106 The Port Multiplier FIS Based Switching feature added in the AHCI 1.2
107 specification, which is required for effective parallel operation of devices
108 behind Port Multipliers, is not yet supported.
110 AHCI hardware is also supported by ataahci driver from
112 subsystem. If both drivers are loaded at the same time, this one will be
113 given precedence as the more functional of the two.
117 driver supports AHCI compatible controllers having PCI class 1 (mass storage),
118 subclass 6 (SATA) and programming interface 1 (AHCI).
129 driver first appeared in
132 .An Alexander Motin Aq mav@FreeBSD.org .